Bill intensifies to Category 4; globe has 5th warmest July on record

Category 4 Hurricane Bill is now the the fourth strongest tropical cyclone to appear on the planet so far this year, and may grow even stronger. Visible and infrared satellite imagery continue to show an impressive, well-organized, hurricane, with plenty of low-level spiral banding and upper-level outflow well-established on all sides except the west. On Bill's west side, upper-level winds from the west are creating a modest 10 knots of wind shear, which is giving the hurricane a bit of a squashed appearance there.

Wind shear is forecast to remain low to moderate, 5-15 knots, for the next four days. Sea Surface Temperatures (SSTs) will rise steadily from 28.5°C today to 29°C on Friday. Total ocean heat content is at a maximum today, and will gradually decline over the next four days. Bill should be able to take advantage of these favorable conditions a remain a major hurricane the next three days.

Water vapor satellite loops show a small "short-wave" trough of low pressure to the north-northwest of Bill, and this trough has turned Bill on a more northwesterly track over the past two days. Bill will miss the Lesser Antilles Islands, and the main impact of the hurricane on these islands will be high waves. The short wave trough (so called because it has a relatively small amplitude and wavelength) is not strong enough to turn Bill due north, and Bill is also expected to miss Bermuda. High waves and sustained winds of 20 - 30 mph are the worst that Bermuda is likely to get from Bill.

An unusually strong "long wave" trough of low pressure (called long wave because of its large amplitude and wavelength) is expected to develop along the U.S. East Coast late this week. This trough will turn Bill to the north, and also bring high levels of wind shear in the 40 - 65 knot range on Sunday. Exactly where this turn occurs is still not clear. The models continue to be in two camps: an eastern camp (GFS, GFDL, HWRF, and ECMWF) that takes Bill 300 - 500 miles east of Cape Cod, and a more western camp (NOGAPS, UKMET) that bring Bill within 150 - 200 miles of Cape Cod. Both sets of models bring Bill ashore over the Canadian provinces of Newfoundland or Nova Scotia. Bill will be weakening rapidly as it makes landfall, and is likely to be a Category 1 hurricane if it hits Nova Scotia, or strong tropical storm if it hits Newfoundland.

Bill's big wavesLarge swells from Bill will begin impacting the U.S. East coast from Florida to Maine beginning Friday night or Saturday morning. Seas will build to 5 - 10 feet in the offshore waters from central Florida northwards to South Carolina, and to 10 - 15 feet from North Carolina to Cape Cod. Near shore, waves will be about 40% less. This will cause a significant coastal erosion event along some portions of the coast. The latest run of the NOAA Wavewatch III model suggests that significant wave heights near Bill's center will reach 50 feet on Sunday. Since maximum wave height is typically about a factor of 1.9 greater than the significant wave height (which is the average trough-to-crest height of the top 1/3 largest waves), a few huge waves near Bill's center may reach 95 feet high.

Possible impacts to New EnglandThe current set of computer model runs predicts that the center of Bill will pass Cape Cod, Massachusetts Sunday afternoon or evening. Tropical storm-force sustained winds of 39 mph or greater currently extend out 185 miles to the west of Bill's center, so that if Bill maintains its current wind distribution, Cape Cod could see sustained winds of about 40 mph Sunday night if the models predicting a more westerly path are correct. However, Bill will not keep this same radius of winds. The hurricane will weaken considerably beginning Sunday morning, once the storm gets caught up in the approaching long wave trough. High wind shear of 40 - 65 knots due to strong southwesterly winds aloft will act to compress the hurricane in the east-west direction, keeping the hurricane's strongest winds away from Cape Cod. The highest winds are likely to be no more than 30 mph on Cape Cod from Bill, if the storm follows the track of the western camp of models nearest to the Massachusetts. A few rain squalls may affect coastal Massachusetts, but the main impact of Bill on New England is likely to be coastal erosion from high waves.

Elsewhere in the tropicsThe remains of Tropical Storm Ana are bringing scattered heavy rain showers to the Bahamas and Florida today. The remains are disorganized, and are not likely to re-develop. The only model calling for a new tropical cyclone to develop in the Atlantic over the next seven days is the GFS model, which predicts development off the coast of Africa about 7 days from now.

Fifth warmest July on record globally; a cold July in the U.S.The globe recorded its fifth warmest July since record keeping began in 1880, according to NOAA's National Climatic Data Center. NOAA rated the period January - July 2009 as the sixth warmest such period on record. NASA's Goddard Institute for Space Studies rated July 2009 as the 2nd warmest July on record, behind July of 1998. For the second month in a row, global ocean Sea Surface Temperatures (SSTs) in July were the warmest on record, 0.59°C (1.06°F) above the 20th century average. This broke the previous July record set in 1998. The record July SSTs were due in part to an ongoing El Niño event in the Eastern Pacific, which has substantially warmed a large stretch of the tropical Eastern Pacific Ocean. As El Niño conditions mature during the coming months, near-record global ocean and land temperatures will probably continue. Now that El Niño conditions have been well-established for three months, the atmosphere has begun to heat up in response. It typically takes up to seven months for the atmosphere to heat up in response to ocean heating from an El Niño. This may explain why June of 2009, which independent assessments by NOAA, NASA, and the UK Hadley center agreed was the 2nd or 3rd warmest June on record at the surface, recorded only average satellite-measured temperatures in the lower atmosphere. In contrast, the July satellite-measured temperatures in the lower atmosphere were the 2nd or 3rd warmest on record, in agreement with the assessments that surface temperatures were the 2nd to 5th warmest on record.

Figure 3. Departure of temperature from average for July 2009. Image credit: NOAA/NCDC.

A cold July for the U.S.For the contiguous U.S., the average July temperature of 23.1°C (73.5°F) was the coolest since 1994, and July temperatures were the 27th coolest in the 115-year record, according to the National Climatic Data Center. Ohio, Illinois, Indiana, Pennsylvania, Iowa, and West Virginia experienced their coolest ever July. Kentucky, Missouri, Michigan, and Wisconsin recorded their second coolest July in history. A strong trough of low pressure parked itself over the eastern portion of the U.S. in July, funneling down plenty of cold air from Canada. In the western U.S., a ridge of high pressure dominated, bringing unusually hot conditions. Arizona recorded its 3rd warmest July on record, and Seattle, Washington recorded its hottest day in history on July 28, notching a 103°F reading. This was 3°F above the previous record set in 1994.

U.S. precipitation was near average in July, with the month ranking 40th wettest in the 115-year record. U.S. tornado activity was above average in July, according to NOAA's Storm Prediction Center. However, no tornado deaths occurred in July.

At the end of July, 14% of the contiguous United States was in moderate-to-exceptional drought. This is a drop from the 19% figure observed at the beginning of the year. These extreme drought regions were exclusively in South and Central Texas.

Quoting TropicTraveler:Melagoo - Opened the link - gave me a chill when I saw how many ships have gone down there. I know in that one storm in the museum virtually every family in town lost family members in one day.

Quoting KerryInNOLA:Bill is not a classic annular hurricane. It may have a few annular characteristics,but thats all. Annular hurricanes are not common. Bill is not going to bust the trough either. Sorry all wishcasters.

Quoting medicroc:nothing irks me more than people coming on to this board with an admonishing tone saying things like "you people are wising for hurricanes, don't you know people die,etc".But I must say one thing:Why in the hell does anyone think we in NYC need some kind of wakeup call. We are awake, have been since September 11, 2001

Im in NYC and Bill would not be a wake up call he would be a catastrophe and we qwill never be able to wake up from ....... you must be joking ....out to sea!!! please

WAs the Long Island Express 1938 a direct NY hit or sideswipe, not sure just asking, I know its forward speed was like 60mph and it was 120mph cat 3 hurricane.

it went right over cen long island in w ny up into cen ontario where it looped back to disapate just n of toronto its forward speed was 70 mphat it landfall on long island therefore the nickname the long island express

Quoting medicroc:And when would these evacuations become mandatory? I mean, if Bill decides to come closer than predicted, how far in advance do emergency officials make that call?

Just curious.Well that is my concern. The person that sounds the alert is setting him/herself up for a big fall if nothing happens. Imagine displacing that many people, closing down the financial mecca of the world. My concern is that after their finished dotting all the i's and crossing all the t's it'll be too late. The political ramifications could be enormous

Maybe it would be best for them to do a voluntary evacuation, before a mandatory would go into effect. If people feel the need to leave then go ahead and leave. That might would help it from getting to bad if a mandatory is called. Course we all hope he makes that turn...

Quoting TropicTraveler:The tides are already so high in the Bay of Fundy I can't even imagine them if they got much higher. Watched a tidal bore come roaring up a river and within a few minutes a peaceful stream was absolutely incredible.

That tidal bore is awesome to whitewater raft on, I've done it multiple times :)

Quoting medicroc:And when would these evacuations become mandatory? I mean, if Bill decides to come closer than predicted, how far in advance do emergency officials make that call?

Just curious.Well that is my concern. The person that sounds the alert is setting him/herself up for a big fall if nothing happens. Imagine displacing that many people, closing down the financial mecca of the world. My concern is that after their finished dotting all the i's and crossing all the t's it'll be too late. The political ramifications could be enormous

And when would these evacuations become mandatory? I mean, if Bill decides to come closer than predicted, how far in advance do emergency officials make that call? Just curious.

Well that is my concern. The person that sounds the alert is setting him/herself up for a big fall if nothing happens. Imagine displacing that many people, closing down the financial mecca of the world. My concern is that after their finished dotting all the i's and crossing all the t's it'll be too late. The political ramifications could be enormous

The 4th storm of the season began its life in the Central Tropical Atlantic on August 15. The storm moved west-northwestward for the first week of its life, while strengthening on the way. As it reached Category 3 strength, it moved more northwestward. Cooler waters weakened the storm, but it managed to hit New York City directly as an 85 mph (137 km/h) hurricane. It was one of 2 hurricanes to directly hit New York throughout the 19th century, with the other being the 1821 Norfolk and Long Island hurricane. This storm was one of four active hurricanes on August 22.from Wiki.

This 1893 storm was the only hurricane I could find that made a direct hit on NYC.

WAs the Long Island Express 1938 a direct NY hit or sideswipe, not sure just asking, I know its forward speed was like 60mph and it was 120mph cat 3 hurricane.

nothing irks me more than people coming on to this board with an admonishing tone saying things like "you people are wising for hurricanes, don't you know people die,etc".But I must say one thing:Why in the hell does anyone think we in NYC need some kind of wakeup call. We are awake, have been since September 11, 2001

The 4th storm of the season began its life in the Central Tropical Atlantic on August 15. The storm moved west-northwestward for the first week of its life, while strengthening on the way. As it reached Category 3 strength, it moved more northwestward. Cooler waters weakened the storm, but it managed to hit New York City directly as an 85 mph (137 km/h) hurricane. It was one of 2 hurricanes to directly hit New York throughout the 19th century, with the other being the 1821 Norfolk and Long Island hurricane. This storm was one of four active hurricanes on August 22.from Wiki.

This 1893 storm was the only hurricane I could find that made a direct hit on NYC.

Quoting BahaHurican:I was about to ask if Sable Island isn't the area they call the "Graveyard of the Atlantic" because they've had so many ships go down there over the years.... something about a wicked reef in the area comes to mind....

Well if they call it that they are right. The museum exhibit said the ships that sank in that one storm had sheltered on the lee side of the island and it just swept over and sank the ships anyway. I'll bet in a bad storm you wouldn't even know it's there.

Quoting medicroc:Plans are to evacuate only those areas that are in direct threat of surge. Those evacuated will be moved to one of 56 shelters centered in the non surge areas within each boro. the 3 million on long Island will be evacuated through NYC. The nightmare of a logistical nightmare.

And when would these evacuations become mandatory? I mean, if Bill decides to come closer than predicted, how far in advance do emergency officials make that call?

Bill's future movement will be highly dependent on the break down of the upper level high now steering the hurricane. We are starting to see more of a break down on the western side of this ridge. Bill will tend to track into a weakness created by this break down causing the hurricane to track more to the northwest tonight through Friday. A strong upper level trough now located over the central United States will move east causing increasing southwest upper level winds over the western Atlantic this weekend. This will help steer the hurricane on a more northerly course between 65 west longitude and 70 west longitude. If the upper level trough moves faster than expected Bill's track will be closer to 65 west. If the upper level trough moves slower then Bill's track will be closer to 70 west. Regardless of the exact track Bill is a large hurricane and its tropical storm force wind field extends outward more than 200 miles from the center of the storm. This will create large and dangerous surf conditions in and around Bermuda along with strong gusty winds. The east coast of the United States especially from Hatteras North Carolina to the coast of Maine will also experience these dangerous surf conditions this weekend. There's still the chance Bill could track close enough to coastal sections of New England, especially Cape Cod to cause not only the dangerous surf but also strong perhaps tropical storm force wind gusts.

In the long term Bill will weaken quickly during Sunday and Sunday night as the hurricane approaches the east or southeast coast of Nova Scotia. Current computer forecasts suggest Bill will threaten Nova Scotia and Newfoundland later Sunday through Monday as it weakens to a category 1 hurricane by Sunday night and to a tropical storm by Monday morning over southern Newfoundland. Atlantic Canada will experience higher than normal surf with dangerous rip currents. The area will experience tropical storm force winds with hurricane force wind gusts along and near the coast of Nova Scotia late Sunday and Sunday night and tropical storm force winds over much of Newfoundland later Sunday night into Monday morning. Heavier rainfall will also impact parts of Nova Scotia and Newfoundland late Sunday and Sunday night and mostly Newfoundland on Monday. Bill should become a non tropical low pressure area as it moves across Newfoundland during Monday morning and will be northeast of Newfoundland by Monday evening.

My projected path from this morning looks pretty good at this hour, especially considering the models have shifted a tad west. I also noticed the NHC now does not have Bermuda in the cone, neither do I.

From 9 am this morning (I'll issue another a little later, likely between 6:30 and 7:30):

Yeah man, looks great for now.. Howd you get all those graphics? I just use paint lol